Conveyer



y 7, 1963 c. w. HUSUM 3,088,579

CONVEYER Filed Oct. 18, 1960 2 Sheets-Sheet 2 an a EAL PH HOG-E AImK/YEYJ spz/ycm 4 5mm 04/5 JR.

United States Patent 3,088,579 CONVEYER Charles W. Husum, Toledo, Ohio, assignor to Owens- Illinois Glass Company, a corporation of Ohio Filed Oct. 18, 1960, Ser. No. 63,300 8 Claims. (Cl. 198-134) This invention relates generally to conveyers for sheet material and more particularly to an apparatus for conveying coated sheet material through an oven.

In sheet metal closure cap manufacturing processes, li-thog-raphed sheets from which the caps are made are first coated on the unlithographed side with, for example, an enamel, then the sheets are passed through a heated oven to bake, set and bond the coating to the base metal. During passage through the oven the sheets are normally in a substantially vertical on-edge position and leaning against longitudinally spaced apart frames or wickets of a conveyer, thereby facilitating flow of heated air over the sheet surfaces.

Conventional conveyers comprise two or more parallel endless chains to which are attached skeletal-like sheet supporting frames or wickets. These frames are disposed at an angle inclined slightly to the vertical in order that sheets positioned between adjacent frames will rest against the frames. In use, such conveyers have been found to produce undesirable results in that the lithographed surface which contacts the frame frequently is abraded or scuffed by said frame with the result that closure caps produced therefrom are not marketable. -In addition, the consequent monetary loss is substantial. Moreover the sheets are non-uniformly heated because the heavy metal frames in the areas of contact with the sheets absorb and hold a substantial amount of the heat which under ideal conditions would instead be absorbed by the sheets. Such non-uniform baking is the cause of, what I term, ghosting. In other words, the precise outline of the frame is apparent on the enamel coated surface, by virtue of lighter lines appearing on that surface, this being the result of localized underbaking.

It has been proposed that these difficulties could be eliminated by preheating the frames. This reduces ghosting but also reduces the viscosity of the coating causing the same to flow. Such results in the production of closure caps having liners of non-uniform thickness and at times actually creates pin-holes in the lining so that bare metal is exposed. In addition, this obviously did not and could not be expected to eliminate the abrasion problem. Thus, despite continued efforts to eliminate these problems they continued to exist and have resulted in the production of substantial amounts of defective and unmarketable caps.

It is therefore an object of the present invention to provide a conveyer that is free of the above described difficulties.

It is a further object of the present invention to provide a baking oven conveyer for coated sheet material that eliminates uneven baking of the sheets.

It is another object of the present invention to provide an apparatus for conveying coated sheet material through a baking oven which apparatus substantially eliminates the common cause for abrasion of the sheet material.

A further object of this invention is to provide an improved sheet metal supporting frame which minimizes the mass or area of metal to metal contact between the frame and sheet to the end that the heat in the oven is utilized to heat the sheets instead of being absorbed to a substantial detrimental extent by the frames or wickets with the resultant ghosting described above.

Numerous other objects and advantages of this invention will become apparent from a reading of the following detailed description taken in conjunction with the drawings in which:

FIGURE 1 is a side elevational view of a baking oven and sheet material conveyer embodying the present invention;

FIGURE 2 is a transverse sectional View taken along lines 2-2 of FIGURE 1 showing one of the sheet supporting wickets or frames;

FIGURE 3 is an end elevational view of one of the wickets or frames attached to a carrying chain;

FIGURE 4 is a perspective view of one of the wickets and its supporting element; and

FIGURE 5 is a perspective view of an enamel coated sheet of tinplate which exhibits the aforementioned ghosting.

In brief, this invention contemplates a multiplicity of continuously advancing relatively rigid skeletal-like sheet supporting frames or wickets, each frame including a plurality of small gauge wires, piano wires, for example, which are in direct contact with the coated sheet and which are, for the most part, spaced from the frame. The frames are arranged in such fashion that the sheets are supported in an on-edge position upon endless carriers for the frames and rest in inclined positions against the small gauge wires carried by said frames and held away from contact with the latter. The small gauge wires which are in contact with the lithographed surface of the sheet do not abrade or scuff this surface because of their very small area and smooth surface. In addition, the low mass of such wires absorbs an absolute minimum amount of oven heat and eliminates ghosting. Obviously other specific devices than illustrated may be utilized in supporting the wires in inclined positions.

Referring now to the drawings which illustrate the preferred embodiment of my invention, the reference numeral 10 denotes a conventional horizontal baking oven through which passes a link chain conveyer 11. Such a conveyer, may well include at least a pair of horizontally spaced, parallel, endless chains 12 which are of conventional construction and have been illustrated diagrammatic-ally. It should be understood that other flexible endless carriers may be used in place of the chains. In the preferred embodiment three chains are used, however it is also possible to accomplish the above described desired results by the use of two or more than three chains. The chains 12 are trained over driving and idler sprockets 16 and 17, respectively, which are located beyond opposite ends of the oven 10. Driving sprocket 16 receives its power from a conventional motor (not shown) and is mounted on a support 18, whereas the idler sprocket 17 is freely rotatably mounted on a support 20.

These chains carry and are connected together by a plurality of skeletal-like frames or wickets 13 which are uniformly spaced apart along the length of the chains 12. The frames 13 are parallel to each other in a direction transverse to the length of the chains 12. The frames 13 may be constructed of iron bars, or any rigid material which will withstand the temperatures of the baking or drying ovens.

These frames may assume any preferred configuration so long as they are of a size and shape adequate to support the sheet material to be conveyed through the oven. Each frame or wicket 13, in the illustrated form, comprises a generally U-shaped member 14, including a pair of legs 19, a cross-bar 35 connecting the outer or free ends of said legs 19 and a brace 15 which may be generally Y-shaped with the forks 36 secured to the crossbar 35 of the U-shaped member 14 and the base thereof secured at its lower end to one of the chains 12.

Secured to and forming the inner links of chains 12 are '2 D a plurality of U-shaped connectors 21 whose bases are disposed in overlapping relationship similarly to the con ventional outer links 22 of the chains 12. These connectors 21 support the frames by means of the legs 19 of the U-shaped member 14 and the Y-shaped brace 15 which fit into the connectors 21 as is more clearly shown in FIGURE 2. They are secured there by any conventional means (not shown) such as a cotter pin. Connectors 21 may be inclined slightly from the plane of the chains in order that the frames 13 may be tilted slightly, thereby providing one method by which the sheets may move through the oven in a slightly tilted position. It is also possible to incline the frames 13 by changing the alignment of the holes 23 in connectors 21.

A small gauge wire 25, such as piano wire, is secured at one end thereof to each of the connectors 21 by a hook 27 or other conventional means. Each wire extends outwardly from the connectors 21, over a circular spacer 26 and then downwardly along the opposite side of the frame 13 to a coiled spring 28 which is anchored to the connectors 21 and which holds the wire 25 under tension.

The circular spacer 26 may have a smooth wire con tacting surface or the same may be peripherally slotted or grooved as indicated. The circular spacers 26 are adapted to hold the wires 25 in spaced relationship to the frames 13 and are positioned along the cross-bar 35 at points substantially perpendicular to the length of the chains 12.

The diameter of the spacers 26 and dimensions of the connectors 21 are such as to position the wires 25 parallel to the frames 13 if the same is inclined slightly from the vertical. If however, the frames 13 are positioned substantially perpendicular to the length of the chains 12, then the spacers 26 and the connectors 21 are positioned in such a manner that the wires 26 passing therebetween are inclined slightly from the vertical. The spacing of the wires 25 from the frames 13 is such that the coated sheet material which is to be passed through the oven 10 is held away from contact with the frames 13 and by gravity in contact with and leaning against the wires 25.

The sheets 30, after being coated, are placed upon the wires 25. of substantially horizontally positioned frames near the entrance end of the oven with the lithographed side resting against the wires. As the conveyor advances the frames 13 toward and into the oven they are brought into a nearly vertical position because the upper reach of the chains 13 are now moving in a substantially horiz ontal plane. Thus the sheets assume nearly vertical positions in which they are on-edge upon the chains and lean against the wires. Since the frames 13 and consequently the wires 25 are slightly inclined from a direction perpendicular to the direction of movement of the chains 13, the'sheets 30, as just explained, tilt and continue to rest against the wires 25 in an on-edge position asis more'clearly shown in FIGURES l and 3. The lower edge of the sheets 30 rests on links of the chains 13. As the sheets move through the oven 19 in the direction of the arrow in FIGURE 1, they are subjected to high temperatures to bake the enamel or other coating that had been placed thereon. Upon leaving the exit end 32 of the oven 10, they are removed automatically or manually and placed in a stack 33.

Referring now to FIGURE it represents an enamel coated sheet 30 of tinplate that has been baked by passing it through a baking oven on a conventional conveyer which does not utilize the wires 25 of this invention as supports for the sheets 30 but rather uses only conven tional frames as the support. The dotted zones or areas 34 represent a typical ghosting pattern or uneven baking produced on such a sheet which ghosting is not present on sheets conveyed through an oven on the apparatus of this invention.

Although my invention has been described for use'with an oven for baking enamel on sheets of tinplate it should be understood that it may be used equally well and with 4 advantageous results in a drying or other heated oven through which sheets, such as steel or aluminum, coated with inks, enamels, etc. are to be passed.

As explained heretofore, this invention completely eliminates the problem of ghosting. In addition, the very thin material used as supports for the sheets also eliminates the abrasion problem.

It will be apparent that modifications may be made in this invention without departing from its spirit and scope as defined in the following claims.

I claim:

1. Means for conveying sheets having at least one coated surface through a heated oven, comprising a multiplicity of advancing skeletal-like sheet supporting frames, each frame including a plurality of small gauge wires for direct supporting contact with a coated sheet, said wires for the greater part being spaced from the frame proper and means for spacing said wires from said frame.

2. Means for conveying surface coated metal sheets in succession through a coating treating zone with the sheets in an on-edge inclined position, comprising a continuously advancing supporting element upon which the sheets rest, a multiplicity of frames carried by said element, each frame carrying a plurality of small-gauge wires spaced from said frame for direct supporting contact with the coated sheets and positioned to hold said sheets inclined to the vertical and means for spacing said wires from said frame.

3. A conveyer for coated sheets comprising a plurality of spaced apart parallel endless chains, a plurality of skeletal-like frames attached to said chains, each frame provided with sheet contacting and supporting wires spaced from the frame proper and disposed in a plane at an angle to the vertical whereby sheets positioned between adjacent frames will rest against the wires and means for spacing said wires from said frame.

4. A conveyor comprising a plurality of horizontally spaced apart parallel endless chains each having an upper reach and all of said reaches lying in a common horizontal plane, a plurality of skeletal-like sheet supporting frames attached to said chains at equally spaced points therealong, each of said frames including a plurality of small gauge wires spaced therefrom and providing supporting contact with one face of a sheet, means for spacing said wires from said frames, said wires providing the sole contact between the frames and sheets, and the frames disposed in an angle to the vertical whereby sheets positioned between adjacent frames will, under the influence of gravity, tilt and rest against said wires.

5. A conveyor for coated sheets comprising a plurality of horizontally spaced apart parallel endless chains each having an upper reach and all of said reaches lying in a common horizontal plane, a plurality of skeletal-like sheet supporting frames attached to said chains at points uniformly spaced apart therealong, each of said frames including a plurality of small gauge wires being substantially parallel to and spaced fromsaid frames and providing supporting contact for said sheets, a plurality of circular spacers attached to said frames at. points remote from said chains and adapted to space said wires from said frames, and said frames being disposed at an angle to the vertical whereby sheets positioned between adjacent frames will, under the influence of gravity, tilt and rest against said wires.

6; An apparatus for transporting coated sheets in an inclined on-edge position through an oven, comprising a plurality of spaced apart parallel endless chains having an upper'reach extending through said oven, a plurality of skeletal-like frames attached to said chains, each of said frames including a plurality of sheet contacting wires spaced forthe greater'part from the frame proper and disposed at an angle to the vertical whereby sheets positioned between adjacent frames will rest against said wires and means for spacing said wires from said frame.

7. An apparatus for transporting coated sheets in an inclined on-edge position through an oven, comprising a plurality of horizontally spaced apart parallel endless chains each having an upper reach extending through said oven and all of the upper reaches lying in a common horizontal plane, a plurality of skeletal-like sheet supporting frames attached to said chains at equally spaced points therealong, each frame including a plurality of small gauge wires parallel to and for the greater part spaced from the frame proper and providing supporting contact with one face of a sheet, means for spacing said Wires from said frames and the frames disposed at an angle to the vertical whereby sheets positioned between adjacent frames will, under the influence of gravity, tilt and rest against said wires.

8. An apparatus for transporting enamel coated sheets in an inclined on-edge position through a baking oven, comprising three horizontally spaced apart parallel endless chains, said chains each having an upper reach extending through said oven and all of said reaches lying in a common horizontal plane, a plurality of skeletal-like sheet supporting frames attached to said chains at points uniformly spaced apart along the latter, each of said frames including three small gauge Wires secured to opposite sides of said frames, said wires being substantially parallel to and for the greater part spaced from the frame proper and providing supporting contact with one face of the sheet, a plurality of circular spacers attached to said frames at points remote from said chains and adapted to space said wires from said frames, and the frames disposed at an angle to the vertical whereby sheets positioned between adjacent frames will, under the influence of gravity, tilt and rest against said wires.

References Cited in the file of this patent UNITED STATES PATENTS 

1. MEANS FOR CONVEYING SHEETS HAVING AT LEAST ONE COATED SURFACE THROUGH A HEATED OVEN, COMPRISING A MULTIPLICITY OF ADVANCING SKELETAL-LIKE SHEET SUPPORTING FRAMES, EACH FRAME INCLUDING A PLURALITY OF SMALL GAUGE WIRES FOR DIRECT SUPPORTING CONTACT WITH A COATED SHEET, SAID WIRES FOR THE GREATER PART BEING SPACED FROM THE FRAME PROPER AND MEANS FOR SPACING SAID WIRES FROM SAID FRAME. 